I'm driving myself nuts trying to figure out what the engine in my 1969 GTO is all about. Here's my dilemma---all of the casting numbers on the block seem correct for a 1969 400cid (i.e. Type code YS,Date code B289,Feb 28,1969,casting number 9790071, production # 0599899) except there is no VIN number stamped on the block front next to the timing chain cover like there should be. There is a nicely machined pad but no number stamped on it! Did some factory engines miss getting the VIN stamped on them or what? All the other component numbers seem right--for example the heads date coded C049/C059(march 4th & 5th, 1969), intake manifold date code C119(March 11,1969) . Any ideas anyone?

Some GM plants stamped the bell housing not all vin. stamps were in a mandatory spot and the whole vin# was not always stamped! and The plant, date, and engine ID codes were stamped at the respective engine assembly plants while the partial VINs (when applicable) were stamped at the final assembly plant. Therefore the two stampings will have different fonts, character sizes, and in some cases will be stamped at different locations on the engine block! I do remember that early on Vin stamps were not manditory it was volintary from plant to plant I don't remember when it became manditory

I understood that all vehicles 1968 and after had to have the partial VIN number stamped on the front of the block where you noted in your thumbnail above.Perhaps not all block manufacturing plants got up to speed as fast as others. The car DATA PLATE indicates the car was assembled in Fremont Calif but who knows where the block was manufactured. Interestingly, the M-40 trans has the correct partial VIN stamped on it. I guess I'll just keep looking elsewhere on the block . If I find it I'll let you know .
Rosylab

That's good to hear Bill although I'm in no mood to rip off my timing chain cover just to have a look. I will look closer at it though--maybe I will be able to see something peering out from under the cover that I may have missed before. Maybe when I pull the engine to change a leaky pan gasket (who came up with that design???) I'll dig a little deeper into this. I'll be able to examine the whole block then. The more I think of this the more I suspect that LATECH might have been on to something when he suggested that this may be a replacement factory engine. That would explain no VIN number. This whole drive train is pretty weird. I know the tranny is original and the rear axle may be as well. It is coded a WB which indicates a 2.56 ratio which was an "economy" option c/w 2-bbl carb on the 400cid with much lower compression.. This gave a 260hp rating I believe . Some owner before me may have ripped out that engine and replaced it with a factory replacement YS. The joys of buying a 43 year old car. In any case, I've since replaced the 2.56 gears and replaced them (they were shot anyway) with an Auburn limited slip. I'm going to bed now to dream of something else.

Has the engine been rebuilt probably since its 40+ years old. Its common for the rebuilder to deck the block and wipe the vin number clean off. On pontiacs its more common since the cr is low a lot of people try to bring it up by decking the block my self included. So i would not be suprised to find the vin missing. Modern cars do not stamp the vin in a location that it can be removed by normal machine work.

If its a collector car. Get the engine build to sign a letter that the vin was in place before the rebuild and the deck was surfaced. Not ideal but it happens. Hopefully you can find the shop that did the work. I have also herd of some acid that will reveal the number even if its removed but not sure this will work on a 40 year old engine. works for guns i know. but probably not engine blocks.

older engine did not have the vins.

Also you are looking for the last 6 or last 3 digits of the vin. Not the entire vin number in most cases.

Some rebuilder and restorers can restamp the vin number on the block. But its shady practise and needs to be done correctly and legaly. LOL

Also factory replacment blocks did not have vins stamped on them since it was a replacement part. FYI you got the block replaced under warranty. This could of happend the first year of its life.

I don't have any history on this car past the guy I bought it from. It was originally bought in Sacramento---that I know because I have a copy of the dealer order form. From there I was told it spent most of it's life in Arizona and eventually ended up in Seattle before the guy I bought it from brought it up to BC (Canada) which is where I am. Who knows how many owners there were or what work was done and by whom in between. I can believe it spent most of its life in Arizona as it's completely rust free and the interior showed all the signs of sun damage. The no rust is the main reason I got it. I suspect the engine has been out of the car at least once because you can see the RTV oozing from the pan gasket and the motor mounts look too new. Maybe it WAS originally an "economy" engine with the low 8.6 CR c/w 2bbl carb. That would explain the WB rear axle with the 2.56 gears. A previous owner may have decked the block to get the CR up. The number on the existing 4bbl indicates it came from a Ram III orIV which might make sense if it was a replacement for the original 2bbl. I'll probably never know for sure unless I tear the motor down and check the innards. In any case, the car runs well and it will only ever be a "driver" for me so it's only general interest that's driving my curiosity. Anyway, the research is fun.

It IS possible, the partial VIN is stanmped vertically along the side of the timing cover, as previously suggested. Usually, it' covered with "yuck", but when cleaned up, readable. There may also be a "SR" stamped alongside the cover. That's a "Service Replacement" (warranty block) and many were "restamped" by dealers early on. I recall putting the codes on a 455SD under instruction from Pontiac, when they replaced one under warranty.

Thank you for refering to the transmission correctly. Many simply call it "TH400", because it is essentially the same except the case. Pontiac called it "M-40".

There's something really cool here, many are missing. You have a '68 GTO!!! (lucky ******!).... The "YS" indicates a 350HP 400 /auto trans. Is the "His and Her's" shifter still there? Let us know when you want to get started on restoration or modernizing! A couple of these guys are real sharp on the Pontiac.

I don't have any history on this car past the guy I bought it from. It was originally bought in Sacramento---that I know because I have a copy of the dealer order form. From there I was told it spent most of it's life in Arizona and eventually ended up in Seattle before the guy I bought it from brought it up to BC (Canada) which is where I am. Who knows how many owners there were or what work was done and by whom in between. I can believe it spent most of its life in Arizona as it's completely rust free and the interior showed all the signs of sun damage. The no rust is the main reason I got it. I suspect the engine has been out of the car at least once because you can see the RTV oozing from the pan gasket and the motor mounts look too new. Maybe it WAS originally an "economy" engine with the low 8.6 CR c/w 2bbl carb. That would explain the WB rear axle with the 2.56 gears. A previous owner may have decked the block to get the CR up. The number on the existing 4bbl indicates it came from a Ram III orIV which might make sense if it was a replacement for the original 2bbl. I'll probably never know for sure unless I tear the motor down and check the innards. In any case, the car runs well and it will only ever be a "driver" for me so it's only general interest that's driving my curiosity. Anyway, the research is fun.

What heads are on it? The YS engine would have come w/16 or 62. The 2bbl engine used 45 heads.

If the engine was originally a 2bbl, they sure did you a favor by replacing it w/a "correct" 4bbl engine for that year. But it makes ME wonder if the 4bbl YS code engine is original and it had the rear end swapped out. But either way, it'll make a nice ride.

It can't be a "68". The VIN number on the dash and trans indicate 1969 and it does NOT have the 1968 and older vent windows. Some of the obvious signs that this a 69 are that the front end nose has the correct 69 lights and the rear has the 1969 bumper with the taillights above not in the bumper per 1968. Everything about the body screams 1969.

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